PASTE button visible and not visible

Hi

I am using version 4.3.1 and Chrome. If I am using the page 

http://rev.ckeditor.com/ckeditor/trunk/7604/_samples/devtools.html

I can click the right mouse button anywhere in the textarea and I get the PASTE entry although the field has just one line of text and no other paragraphs following. 

If I try this in my own instance I have the PASTE entry just in the first line of text, below this I get the context menu of the browser. 

How can I correct this?

Thank you for any help
Urs